National EHE support:

Home Education UK - extensive online resource for home educators.
Education Otherwise - "UK-based membership organisation which provides support and information..."
HEAS - "... advice and practical support for families who wish to educate their children at home"
HE-Special.org  - information on home educating children with special needs.
Home Education in the UK - all aspects of HE covered with a more personal touch, plus useful links.
THENuk - a national, not for profit network of support and resources for home educators.
 

Educational discounts and memberships:

The National Trust - For free entry to NT properties during term-time, apply for a yearly Education Group Membership (2010 price £32).  The NT now require HE families to have public liability insurance (min. indemnity of £5m) in order to take advantage of this type of membership.  If you belong to an HE group, get together and purchase cheap public liability insurance from someone like Finance ReDirect for about £45/yr.  Then purchase the Education Group Membership as an HE group not a family; this allows up to 50 children/students plus attending adults during each single visit.  Individual families from the group can use the card or group visits can be arranged.  For around £80 a year, many families (max. 50 kids) can benefit from this educational discount.

English Heritage - Free Educational visits - Home Educating families are admitted free to properties at the booking office’s discretion.  Bookings need to be made in advance and it is easier and often necessary to prove you are home educating.  Proof of HE can be by way of membership to EO, HEAS etc or other HE groups or sometimes with a National Trust Education Group Membership card if you have one.